Tag Archives: Magnets

Scientists discover magnets out of liquid

Magnets are a key part of modern industry and our daily lives and have become essential in many devices such as electronics and medical devices. All, though, are rigid. But that’s now set to change thanks to a new scientific discovery.

Conventional magnets could be revolutionized by this new discovery. Credit: Bart Heird (Flickr)

 

A team of scientists at Berkeley Lab developed a technique for 3D-printing structures out of liquid, which could lead to a revolutionary class of printable soft devices for a variety of applications – from artificial cells to flexible liquid robots.

“We’ve made a new material that is both liquid and magnetic. No one has ever observed this before,” said Tom Russell, a visiting scientist at Berkeley Lab and professor at the University of Massachusetts. “This opens the door to a new area of science in magnetic soft matter.”

Russel worked for the past seven years on developing a new class of materials, 3-D-printable all-liquid structures. One day, Russell and the current study’s first author Xubo Liu came up with the idea of forming liquid structures from ferrofluids — solutions of iron-oxide particles that become strongly magnetic.

They used a 3-D-printing technique to print droplets from a ferrofluid solution containing iron-oxide-nanoparticles. The iron oxide nanoparticles crowded towards the surface of the droplet, forming a shell at the interface between the water droplets and the oil suspension.

Then they placed the droplets near a magnetic coil to magnetize them. Just like ferrofluid, the iron oxide particles were attracted to the magnet. So far, all normal. But when the researchers moved the magnetic coil away, it got less normal.

When ferrofluid is removed from the presence of a magnetic field, the nanoparticles fall into disarray, and the fluid just becomes sort of blobby. But with this new liquid, the nanoparticles started spinning towards each other in unison, like synchronized swimmers. They had retained their magnetism.

The team continued to investigate and found that exposing the liquid to a magnetic field causes the magnetic poles of the nanoparticles to align in the same direction. But when the magnetic field is taken away, there’s no room for the surface particles to drift because they’re jammed so closely together.

Liu and Russell plan to continue research at national labs in the US to develop even more complex 3-D-printed magnetic liquid structures, such as a liquid-printed artificial cell, or miniature robotics that move like a tiny propeller for noninvasive yet targeted delivery of drug therapies to diseased cells.

The research has been published in Science.

Credit: University of Kyoto.

The magnetic North Pole has shifted, but we can’t update it because of the US government shutdown

Credit: University of Kyoto.

Credit: University of Kyoto.

Hundreds of miles beneath our feet, floating molten liquid is churning away, driving the planet’s magnetic field like a huge electromagnet. It creates our planet’s north and south magnetic poles. These poles do not correspond to the geographic poles, which mark the ends of Earth’s axis of rotation. In fact, their location changes — daily. What’s more, the magnetic poles even flip from time to time. 

Scientists have known this for quite a while and have tracking magnetic pole migrations with high precision for well over a century. This means you shouldn’t be worried about click-bait headlines that announce magnetic pole shifts as something out of the ordinary or even potentially catastrophic. It’s all totally harmless. But what seems to be happening in the last decade is an acceleration in the rate at which the North magnetic pole is moving towards the direction of Siberia and away from Canada.

True North is relative

Historically, researchers recalculate the position of the magnetic North Pole every five years, which is then synced with global navigation systems, such as GPS. The World Magnetic Model is supervised by NOAA and the British Geological Survey, and its most recent update was supposed to happen on January 15 — but it didn’t. The reason behind it is that NOAA, a US federal agency, is currently inactive due to the ongoing government shutdown.

Credit: NOAA.

Credit: NOAA Website screenshot.

For most of the previous century, the pole has moved around nine miles each year. However, since the 1990s, the migration has sped up to 35 miles a year. Over the last 150 years, the magnetic pole has crept north over 1,000 kilometers. It’s not clear why this acceleration is occurring due to gaps in our knowledge of how the planet’s core behaves. One leading hypothesis suggests that liquid molten iron under Canada is being dragged toward Siberia. In the meantime, the magnetic South Pole has barely moved, which is another mystery.

What’s more, a geomagnetic pulse occurred beneath South America in 2016. That was right after a 2015 update to the World Magnetic Model, prompting scientists to schedule a revision earlier than the planned 2020 update. This update should have been online this week were it not for the government shutdown. In the meantime, those engaged in navigation requiring great precision around the North Pole will have to wait — and it’s anybody’s guess for how long.

The new model has the North Pole a good 25 miles away from the one previously predicted. This gross discrepancy means that updates in the future will have to be made much more often than before, preferably yearly. Yet normal folks shouldn’t be too worried since the error gets smaller and smaller the farther away you get from the North Pole. If you live in the United States, your compass should be pointing northward as before with reasonable accuracy.

 

Single-atom magnets used to create data storage one million times more dense than regular hard disks

A team of researchers has created the smallest and most efficient hard drive in existence using only two atoms. This technology is currently extremely limited in the amount of data it can store, but the technique could provide much better storage when scaled up.

Image credits Michael Schwarzenberger.

Hard drives store data as magnetic fields along a disk housed inside the drive. It’s split into tiny pieces and each acts like a bar magnet, with the field pointing either up or down (1 or 0) to store binary information. The smaller you can make these areas, the more data you can cram onto the disk — but you can’t make them too small, or you risk making them unstable so the 1’s and 0’s they store can and will switch around.

What if you used magnets that remained stable even when made to be really tiny? Well, those of you that remember physics 101 will know that cutting a magnet in two makes two smaller magnets. Cut them again in half and you get four, then eight and so on smaller magnets — but they also become less stable.

But a team of researchers has now created something which seems to defy all odds: stable magnets from single atoms. In a new paper, they describe how using these tiny things they created an atomic hard drive, with the same functionality as a traditional drive, but limited to 2 bits of data storage.

Current commercially-available technology allows for one bit of data to be stored in roughly one million atoms — although this number has been reduced to 1 in 12 in experimental settings. This single-atom approach allows for one bit of data to be stored in one single atom. A scaled-up version of this system will likely be less efficient, but could increase current storage density by a factor of 1,000, says Swiss Federal Institute of Technology (EPFL) physicist and first author Fabian Natterer.

Holmium bits

Looks hairy.
Image source Images of Elements / Wikipedia.

Natterer and his team used holmium atoms, a rare-earth metal, placed on a sheet of magnesium oxide and cooled to below 5 degrees Kelvin. Holmium was selected because it has many unpaired electrons (which creates a strong magnetic field) sitting in a close orbit to the atom’s nucleus (so they’re relatively well protected from outside factors). These two properties taken together give holmium a strong and stable magnetic field, Natter explains, but it also makes the element frustratingly difficult to interact with.

 

The team used a pulse of electric current released from the magnetized tip of scanning tunneling microscope to flip the atoms’ field orientation — essentially writing data into the atoms. Testing showed that these atomic magnets could retain their state for several hours, and showed no case of spontaneous flip. The same microscope was used to then read the bits stored in the atoms. To double-check that the data could be reliably read, the team also devised a second read-out method. By placing an iron atom close to the magnets and tuning it so that its electronic properties depended on the orientations of the 2-bit systems. This approach allowed the team to read out multiple bits at the same time, making for a faster and less invasive method than the microscope reading technique, Otte said.

It works, but the system is far from being practical. Two bits is an extremely low level of data storage compared to every other storage method. Natterer says that he and his colleagues are working on ways to make large arrays of single-atom magnets to scale-up the amount of data which can be encoded into the drives.

But the merits and possibilities of single-atom magnets shouldn’t be overlooked, either. In the future, Natterer plans to observe three mini-magnets that are oriented so their fields are in competition with each other, making each other continually flip.

“You can now play around with these single-atom magnets, using them like Legos, to build up magnetic structures from scratch,” he says.

 

Other physicists are sure to continue research into these magnets as well.

The full paper “Reading and writing single-atom magnets” has been published in the journal Nature.

Magnets anchored on Mars’ orbit would make the planet a second Earth, NASA says

Mars could be returned to its habitable glory days easier than you’d believe, NASA researchers say. All it would take is a man-made magnetic field to allow the red planet’s atmosphere to thicken and foster more Earth-like conditions.

Mars with an atmosphere and water wouldn’t be a half-bad place to settle.
Image credits Ittiz / Wikipedia.

Mars is a pretty desolate place. Blood red and bone dry at the same time, it’s either way too cold or much too hot depending on where you happen to be on its surface. There’s nothing good to breathe and it’s also pretty radioactive. In short, Mars isn’t much to write home about — unless you’re writing to complain about how unwelcoming it is.

But it wasn’t always like this, and it doesn’t have to stay this way. Scientists believe that Mars was once surprisingly Earth-like, with water-filled oceans and a surprisingly comfortable climate for an alien world. As the planet’s magnetic field weakened and finally collapsed billions of years ago, solar winds stripped it bare of its atmosphere leaving behind a cold and barren piece of rock.

That magnetic field is the key to NASA’s bold plan to making Mars an awesome place for future generations of human colonists.

Is it a bird? Is it a plane? It’s a magnet!

NASA simulations show that a powerful-enough magnetic shield propped up into space between the Sun and Mars could push away solar winds and allow the red planet to naturally regrow its atmosphere.

The results were presented at the Planetary Science Vision 2050 Workshop last week, when Planetary Science Division director Jim Green said anchoring an “artificial magnetosphere” into space between Mars and the Sun should shield the planet in the magneto-tail (a teardrop-like shape or magnetic ‘wake’) that trails behind this protective field.

“This situation then eliminates many of the solar wind erosion processes that occur with the planet’s ionosphere and upper atmosphere allowing the Martian atmosphere to grow in pressure and temperature over time,” the researchers explain in an accompanying paper.

“Much like Earth, an enhanced atmosphere would: allow larger landed mass of equipment to the surface, shield against most cosmic and solar particle radiation, extend the ability for oxygen extraction, and provide ‘open air’ green-houses to exist for plant production, just to name a few,” they said during the presentation.

It would take surprisingly little time, too. Their figures show that in the absence of solar wind erosion, Mars’ atmosphere would go up to as much as one half of Earth’s atmospheric pressure in a matter of years.

The team agrees that at first glance, the concept may seem “fanciful”. But they point out to existing mini-magnetosphere technologies under development to shield astronauts and spaceships from radiation during deep space missions — technology which could be scaled up to protect a whole planet.

Still, it remains a highly theoretical plan with a high potential of not-going-according-to-plan. We don’t yet have the technology to make it happen, so we got our work cut out for ourselves. It would also be a huge engineering challenge to create, maintain, and properly place these magnets on the firmament.

But we understand what needs to be done and we could probably have the means to do so in a few years. If it does work, the magnets would turn Mars from a place where we’d need domed cities to Earth-like conditions in a few generations. That’s a huge payoff — a whole world’s worth of payoffs.

“It may be feasible that we can get up to these higher field strengths that are necessary to provide that shielding. We need to be able then to also modify that direction of the magnetic field so that it always pushes the solar wind away,” Green said.

“This is not terraforming as you may think of it where we actually artificially change the climate, but we let nature do it, and we do that based on the physics we know today.”

The team will continue refining the idea to get a more accurate estimate of how long the climate-altering effects would take.

“If this can be achieved in a lifetime, the colonisation of Mars would not be far away.”

The findings were presented at the Planetary Science Vision 2050 Workshop.